1. Field of the Invention
The present invention relates to a front structure of a vehicle body, which is to enhance the safety of a pedestrian when the vehicle running at a low speed has a minor collision with the pedestrian.
2. Description of the Related Art
In recent years, there have been proposed front structures of vehicles in each of which protection of a pedestrian is taken into consideration when the vehicle running at a low speed has a minor collision with the pedestrian.
For example, as disclosed in Japanese Patent Unexamined Publication No. Hei. 11-78732 and shown in FIGS. 9 to 11, a front structure of vehicle has an upper side bumper beam 102 and a lower side bumper beam 103. The front face of the upper side bumper beam 102 is covered with a bumper face 101 made of flexible resin. The upper side bumper beam 102 is extended in a width direction of the vehicle at a front part of a vehicle body. The upper side bumper beam 102 and the lower side bumper beam 103 are supported by a radiator panel 106 at the front part of the vehicle body through an upper side bumper stay 104 and a lower side bumper stay 105, respectively.
The upper side bumper stay 104 has a double structure constituted of a long outer pipe stay 107, and a short inner pipe stay 108. The long outer pipe stay 107 is secured to both of the upper side bumper beam 102 and the radiator panel 106. The short inner pipe stay 108 is secured only to the radiator panel 106. The outer pipe stay 107 is constituted of a front side stay 107a having a higher strength and a rear side stay 107b having a lower strength. The front side stay 107a is expanded toward its front end side, as shown in FIG. 10.
Furthermore, the lower side bumper stay 105 is secured to the lower side bumper beam 103 with its front end side, and to the radiator panel 106 with its rear end through a bracket (not illustrated). The upper side bumper stay 104 has a strength in the longitudinal direction determined to be lower than that of the lower side bumper stay 105.
Then, when the vehicle running at a low speed has a minor collision with a pedestrian M as schematically shown in FIG. 10 illustrating a state before the collision and in FIG. 11 after the collision, for example, the upper side bumper beam 102 abuts against a lower limb R near a knee H and the lower side bumper beam 103 abuts against a lower part of the lower limb R.
At this time, the low strength rear side stay 107b of the upper side bumper stay 104 supporting the upper side bumper beam 102 is compressed to be crushed and deformed, and the lower side bumper stay 105 itself is compressed to be crushed and deformed, which relieves an impact. In such a case, the upper side bumper stay 104, having the strength determined to be lower than that of the lower side bumper stay 105, is more largely deformed. This produces a force acting to turn the lower limb R of the pedestrian in directions indicated by arrows A as shown in FIG. 11, that is, in the direction of scooping up an under part of the lower limb R. Thus produced force reduces a bending angle xcex8 appeared at the knee H to reduce the impact load imposed on the knee H. This appropriately controls behavior of the lower limb R at the collision to bring reduction in the load on the knee H.
In the above structure, for a large impact force, it is provided so that both of the front side stay 107a having a high strength and the inner pipe stay inside stay 108 are compressed to be crushed and deformed.
According to the above Japanese Patent Unexamined Publication No. Hei. 11-78732, protection of a leg of a pedestrian, particularly of the knee which is susceptible to be damaged, is provided when a vehicle running particularly at a low speed has a minor collision with the pedestrian.
In the above bumper structure, the upper side and lower side bumper stays 104 and 105 are disposed at a spot near each of the right and left ends of the vehicle. Therefore, when the pedestrian M comes into a minor collision with the upper side and lower side bumper beams 102 and 103 near the upper side and lower side bumper stays 104 and 105, for example, the rear side stay 107b and the lower side bumper stay 105 are compressed to be crushed and deformed to exhibit required performance. However, when the pedestrian M is collided with near the central part of each of the upper side and lower side bumper beams 102 and 103, a force due to an imposed load is distributed to the upper side and lower side bumper stays 104 and 105 at each of the right and left ends. This possibly makes the rear side stay 107b and the lower side bumper stays 105 less compressed to be slightly crushed and deformed to prevent them from exhibiting the required performance.
In addition, there is fear that the reduced strength of the upper side bumper stay 104 accompanies reduction in rigidity for supporting the upper side bumper beam 102 to make a sufficient bumper function unachievable when a large impact load is exerted.
Furthermore, the lower bumper beam 103 placed in front of the radiator panel 106 necessitates conserving a space therefor to restrict design flexibility of the front part of the vehicle. Along with this, it is feared that increased number of parts leads to increases in manufacturing cost and parts stock control cost.
Accordingly, it is an object of the present invention to provide a front structure of a vehicle body which can provide the design flexibility of the front part of a vehicle and reduction in the number of parts, and along with this, can obtain a sufficient bumper function and sufficient reduction of damage of the pedestrian.
In order to achieve the above object, the front structure of a vehicle body according to the invention, comprises a bumper and a radiator panel. The radiator panel has an upper frame and a lower frame both extendedly provided in the width direction of the vehicle at a front part of the vehicle body. The bumper is extendedly provided in a width direction of the vehicle in front of the radiator panel. The bumper comprises an upper side bumper beam extendedly provided in the width direction of the vehicle above the lower frame, an upper part bumper extendedly provided in the width direction of the vehicle and having an upper side impact absorbing material provided between the upper side bumper beam and an upper bumper face, the lower frame of the radiator panel, and a lower part bumper extendedly provided in the width direction of the vehicle and having an lower side impact absorbing material provided between the lower frame and an lower bumper face.
In the above-mentioned structure, the lower and upper bumper faces are integrally formed as a sole bumper face unit.
According to the invention, by forming the lower part bumper with the lower side impact absorbing material provided between the lower frame of the radiator panel and the bumper face, in providing the bumper having the upper part bumper and the lower part bumper both extendedly provided in the width direction of the vehicle at a front part of the vehicle body, the lower frame of the radiator panel is allowed to function as a bumper beam of the lower part bumper. This necessitates no space for separately providing a bumper beam of the lower part bumper to ensure the design flexibility of the front part of the vehicle. Along with this, the number of parts is reduced to allow the structure to achieve lightweight with a simplified constitution.
Furthermore, the upper side impact absorbing material and the lower side impact absorbing material, extendedly provided along the upper side bumper beam constituting the upper part bumper and the lower frame, respectively, have approximately the same cross-sectional profile at any arbitrary position in the width direction of the vehicle. This can ensure a uniform bumper function.
In the structure according to the present invention, it is advantageous that, the radiator panel is made inclined so that a front face of the radiator panel is faced up.
According to the above-mentioned structure, by making the radiator panel inclined, a highly rigid structure such as a hood locking device disposed above the radiator panel can be shifted toward the rear of the vehicle body. Along with this, it becomes possible to incline the front part of the vehicle body, which can control the behavior of a lower limb of a pedestrian when the vehicle has a minor collision with the pedestrian while running at a low speed to reduce damage of the pedestrian.
In the structure according to the present invention, it is advantageous that, the lower side impact absorbing material has a strength against a longitudinal load higher than that of the upper side impact absorbing material.
According to the above-mentioned structure of the present invention, when a vehicle running at a low speed has a minor collision with the pedestrian, the upper part bumper butts the lower limb near a knee and the lower part bumper beam butts a lower part of the lower limb. However, the lower side impact absorbing material, having a strength against a longitudinal load higher than that of the upper side impact absorbing material, is compressed to be crushed and deformed with an amount smaller than that of the upper side impact absorbing material. This makes the lower part bumper push the lower part of the lower limb to scoop it up, and makes the upper part bumper relatively moves the lower limb near the knee backward to provide the whole lower limb a turning force to reduce an impact load on the knee. Therefore, a bending angle appeared at the knee can be made small to allow damage particularly to the knee to be reduced.
In the structure according to the present invention, it is advantageous that, the lower part bumper is provided with a top end position of the bumper face thereof being set ahead of a top end position of the bumper face of the upper part bumper.
According to the above-mentioned structure of the present invention, the top end of the lower part bumper is positioned ahead of the top end of the upper part bumper. Therefore, when a pedestrian has a minor collision with the bumper, the lower part bumper first butts a lower part of the lower limb, and then, the upper part bumper butts the lower limb near a knee. This can provide the lower limb a turning force to allow damage to the knee to be reduced.
The above-mentioned object can also be achieved by, according to the present invention, a front structure of a vehicle body having a radiator panel extendedly provided in a width direction of a vehicle with a radiator mounted thereon and having structures disposed near an upper end of the radiator panel in a front end part of a hood, the radiator panel is made inclined relative to a vertical direction so that a front face of the radiator panel is faced up.
According to the invention as described above, by making the radiator panel inclined relative to a vertical direction, a highly rigid structure such as a hood locking device disposed at the front end of a hood can be shifted toward the rear of the vehicle body. Along with this, it becomes possible to incline the front part of the vehicle body, which can control the behavior of a lower limb of a pedestrian when the vehicle running at a low speed has a minor collision with the pedestrian to reduce damage of the pedestrian.
Note that the above-mentioned object can also be attained by a front structure of a vehicle body, according to the present invention comprising:
a radiator panel including an upper frame and a lower frame which are extended in a width direction of the vehicle body and are located at a front part of the vehicle body in a longitudinal direction of the vehicle body;
a bumper extended in the width direction of the vehicle body and located in front of the radiator, the bumper including,
an upper side bumper beam extended in the width direction of the vehicle body and located a position higher than the lower frame of the radiator in a vertical direction,
an upper part bumper extended in the width direction of the vehicle body and having an upper bumper face and an upper side impact absorbing material provided between the upper side bumper beam and the upper bumper face, and
a lower part bumper extended in the width direction of the vehicle body and having an lower bumper face and a lower side impact absorbing material provided between the lower bumper face and the lower frame of the radiator, whereby the lower frame of the radiator operates a lower side bumper beam function.
Further, the above-mentioned object can further be achieved by a front structure of a vehicle body, according to the present invention, comprising:
a radiator panel extended in a width direction of the vehicle body and located at a front part of the vehicle body in a longitudinal direction of the vehicle body;
a front end part of a hood of the vehicle body including a rigid component which is located in the front end part,
wherein the radiator panel is made inclined relative to a vertical direction so that a front face of the radiator panel is faced up.